title: Traumatic brain injury may be an independent risk factor for stroke.
abstract: OBJECTIVE
  To explore whether traumatic brain injury (TBI) may be a risk factor for subsequent ischemic stroke.
  
  
  METHODS
  Patients with any emergency department visit or hospitalization for TBI (exposed group) or non-TBI trauma (control) based on statewide emergency department and inpatient databases in California from 2005 to 2009 were included in a retrospective cohort. TBI was defined using the Centers for Disease Control definition. Our primary outcome was subsequent hospitalization for acute ischemic stroke. The association between TBI and stroke was estimated using Cox proportional hazards modeling adjusting for demographics, vascular risk factors, comorbidities, trauma severity, and trauma mechanism.
  
  
  RESULTS
  The cohort included a total of 1,173,353 trauma subjects, 436,630 (37%) with TBI. The patients with TBI were slightly younger than the controls (mean age 49.2 vs 50.3 years), less likely to be female (46.8% vs 49.3%), and had a higher mean injury severity score (4.6 vs 4.1). Subsequent stroke was identified in 1.1% of the TBI group and 0.9% of the control group over a median follow-up period of 28 months (interquartile range 14-44). After adjustment, TBI was independently associated with subsequent ischemic stroke (hazard ratio 1.31, 95% confidence interval 1.25-1.36).
  
  
  CONCLUSIONS
  In this large cohort, TBI is associated with ischemic stroke, independent of other major predictors.
authors.affiliation: Department of Veterans Affairs, VA Center for Clinical Management and Research, Ann Arbor VA Healthcare System, Ann Arbor, MI, USA. jamesbur@umich.edu
authors.forename: James F
authors.initials: JF
authors.lastname: Burke
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Stulc
authors.forename: Lesli E
authors.initials: LE
authors.lastname: Skolarus
authors.forename: Erika D
authors.initials: ED
authors.lastname: Sears
authors.forename: Darin B
authors.initials: DB
authors.lastname: Zahuranec
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Morgenstern
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001930:Brain Injuries / Q000150:complications*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000209:etiology*; D016896:Treatment Outcome; D055815:Young Adult